The reason you have more veins showing up after the 1st session, is due to the fact that after the treated vein dicipates, the smaller veins have to take over for the lost vein. Therefore they are under greater pressure, and often fail, especially if you are not wearing compression stockings. the "new" veins that pop up can be cured with further sessions of sclerotherapy. You can continue to have the therapy until you find no more varicosity. It can be expensive, and can take a few months to complete the treatment, but it is faster and easier than surgery. Your body is the reason for more and more veins popping up, not the therapy.